Adjustable well screen assembly

ABSTRACT

An adjustable well screen assembly having a sand screen which is wrapped around a perforated base pipe and a perforated sleeve which is movably disposed concentrically inside the base pipe between a first, closed, and a second, open, position. In the first position of the sleeve the perforations of the sleeve and base pipe are unaligned and hydraulically isolated from each other and flow of fluids from the outer diameter of the screen into the interior of the sleeve is inhibited. In the second position the perforations of the sleeve and the base pipe are aligned and connected in fluid communication with each other and fluids are permitted to flow from the formation through the sand screen and the perforations of the sleeve and base pipe into the interior of the sleeve.

FIELD OF INVENTION

This invention relates to an adjustable well screen assembly forcontrolled inflow of fluids from a hydrocarbon fluid containingformation into the production tubing of a hydrocarbon fluid productionwell. The invention also relates to a hydrocarbon fluid production well,which is equipped with one or more adjustable well screen assemblies.

BACKGROUND OF INVENTION

The art of completing wells to exclude solids particles produced by wellfluids is commonly known in the literature as gravel packing.

It is common practice in the construction of wells bored into the earthto dispose steel casing or other tubular conduits inside of the well. Insome well constructions the casing is grouted into the bore by placingportland cement in the annular space between the casing and the wellbore. The casing can be deployed through the depth where the productivesubterranean formation or plurality of formations is encountered belowthe surface. In the former the well completion is referred to thosefamiliar with the art of well completions as open hole completions,whereas those well completions where the casing and cement is runthrough or past the depth of the productive formation is known to thosefamiliar with the art of well completions as cased holes. In either caseof open hole completions or cased hole completions it is well practisedart to dispose across the production formation depths sand screens,slotted pipes, or pipes with holes pre-perforated at surface into thewell casing on a second continuous tube known in the literature asproduction tubing.

Production tubing is disposed inside of the casing extending from thesurface to a depth closer to the production formation. It is oftendesirable to place a packer on the end of the production tubing to forcewell fluids up the tubing and avoid fluids being produced up the casing.The production tubing is then a removable pipe that is disposed in wellsgenerally in jointed lengths of 40 feet (about 12 m), but can bedeployed as a continuous tubing string in what is commonly known in theoil and gas industry as continuous tubing. It is common practice todeploy in production tubing string various apparatus to allow for wellfluid control. It is also common to control such devices from surfaceusing electrical and hydraulic tubes disposed simultaneously with theproduction tubing and connected to the outer diameter of the productiontubing. These hydraulic tubes are known to those familiars with the artof well completions as control lines.

In the cased hole completions it is common practice to run explosivecharges into the well after the casing is cemented across the productiveformation depths and perforate holes through the casing and cement intothe productive formation to create a path for fluid flow into the well.

In many wells either in cased or open hole completions unwantedformation solids are produced into the well along with the productionfluids. These solids are often undesirable and many methods of stoppingthese solids from flowing into the well whilst producing the fluids arewell defined in the literature as the art sand control. One of the morefamiliar methods of stopping solid flow is to perform a gravel pack.

A gravel pack is performed by placing a known size of sand, which isreferred to as the gravel, into the well across the production formationto create a filter medium to stop or reduce the flow of solid materialsfrom the formation into the well. The gravel is most commonly prohibitedfrom flowing into the well by a device commonly know as a well screen.The well screens are designed to keep the specialized sand mesh, knownas the gravel, in place in the annular space between the casing or wellbore outside of the screens forming the filter media.

The current methods of placing a gravel pack is requires that thescreens be deployed in the well on a tubing string from surface untilthe screens are at the depth of the producing formation. At this pointsand is placed around the screens by various methods of pumping,circulating, and other wise dispose sand around the screens. Once thesand is placed around the screens the tubing string is detached from thescreens and extracted from the well. Thereafter the production tubingwith packers, control lines, sliding sleeves, and packers are disposedin the well above the screens. Hence the screens are detached from theproduction string in the common known methods of the industry.

It is current practice to build the well screens out of wire wrap weldedto bars running parallel to the screen axis and said bars are placedaround a pipe extending the length of the screen with holes through thepipe. This pipe is commonly known to those familiars with the art as thebase pipe and forms the structure to which the wire wrap and welded barsare attached. Hence the commonly known well screen consists of wire wraphelically wrapped around the circumference of the screen attached towelded bars that are fitted onto the outer diameter of base pipe. Inother designs of sand screens the screen is manufactured with sinteredmaterials located between the wire wrap or in some cases outside of thewire wrap. In all cases the screen has an inner pipe base that holes orother geometric penetrations to allow fluids to flow into the screensinner diameter.

The well screen lengths disposed in wells vary in length to accommodatethe depth and heights of production zones. To accommodate deployment ofscreens they are run in sections and connected on surface to match theheight of the production zones.

In many wells there exists in one common well bore multiple productionformations that are perforated or otherwise left open hole to allowsimultaneous production from several formations at varying depths intothe well bore and up the production casing. Often in these multipleproduction formations wells the different formations in the earth areseparated by lithology that does not have productive fluids often timesdue to lower permeability and porosity. With the current art thesevarying production formations are completed simultaneously and flow intoa common production tubing to surface. It often occurs that oneproductive formation will produce less fluids, or unwanted fluids, orfor resource management reasons the varying formations may be moredesirably produced at different flow rates or be produced at differenttimes. In the case of gravel packed wells the methods to shut ofproduction from a formation in a well with multiple productionformations producing simultaneously into a common well bore requiresmechanical well intervention techniques none to those familiar to theart. These intervention techniques can include, squeeze cementing, thesetting of plugs via wireline and rig methods, and the pulling ofproduction tubing, control lines, electrical cable, packers, sleeves andother disposed subterranean devices in the well. The above prior arttechniques require mechanical intervention into the well with pipes,wireline, or pumped chemicals into the well bore to affect the inflow offluids into and through screen systems.

U.S. Pat. No. 5,447,201 discloses an adjustable fluid inflow assemblyfor an oil or gas well where the influx of fluids from a plurality ofannular inflow zones is controlled by a series of annular disk shapedvalves which are each arranged between a downstream end of each inflowzone and a production tubing passing therethrough.

A disadvantage of the known assembly is that all fluid entering anannular inflow zone needs to be discharged through an annular diskshaped valve and the fluid flow rate in each valve is therefore highwhich causes a high rate of wear of the valve. The current inventionaims to alleviate this and other disadvantages of the known well inflowcontrol assembly such that production formations can be shut off ortheir fluid production reduced from production zones by non-interventionmethods from surface.

SUMMARY OF THE INVENTION

The adjustable well screen assembly according to the invention theretocomprises a sandscreen which is arranged around a perforated base pipeand a perforated sleeve which is arranged concentrically relative to thebase pipe and is movable relative to the base pipe between a first and asecond position. In said first position of the sleeve the perforationsof the sleeve and base pipe are hydraulically isolated from each otherand flow of fluids from the outer diameter of the screen into theinterior of the sleeve is inhibited. In said second position theperforations of the sleeve and the base pipe are connected in fluidcommunication with each other and fluids are permitted to flow from theformation through the sandscreen and the perforations of the sleeve andbase pipe into the interior of the sleeve.

Preferably, the sleeve is arranged within the base pipe and the outerdiameter of the sleeve is slightly smaller than the inner diameter ofthe base pipe and the sleeve is connected to an actuator, such as ahydraulic or electrical motor, which is designed to rotate and/oraxially translate the sleeve within the base pipe.

Optionally, the actuator is designed to rotate and/or translate thesleeve such that the sleeve is positionable in a range of intermediatepositions between the first and second position, in which intermediatepositions the perforations of the sleeve and base pipe form adjustableflow restrictions which can be gradually opened and closed.

The sandscreen may be equipped with one or more sensors for monitoringphysical parameters such as the pressure, temperature, velocity and/orcomposition of the fluids flowing through the screen and the actuator isdesigned to move the sleeve between the first and second positionthereof in response to signals generated by at least one of the sensorsdeployed in the screen system.

The invention also relates to a hydrocarbon fluid production wellcomprising a hydrocarbon fluid inflow zone which is equipped with aplurality of axially spaced adjustable well screen assemblies withperforated base pipes in which perforated sleeves are movably arrangedwherein the perforated base pipes of adjacent adjustable well screenassemblies are interconnected by blank pipe sections on which anexpandable packers is arranged which provides a fluid seal in theannular space between the outer surface of the blank pipe section andthe inner surface of the wellbore.

In such case it is preferred that the sleeve of each adjustable wellscreen assembly is movable between the first and second positionindependently of position of the other sleeve or sleeves.

The present invention teaches an improved method of disposing wellscreens in to wells such that production formations fluid flows into thewell can be controlled by subterranean devices disposed in the wellattached to well screen systems of this invention.

Thus the present invention provides an apparatus to allow for wellscreen system to be disposed into well bores simultaneously withproduction tubing, and control tubes deployed continuously from surfaceto the sand screen system depths. Hence this invention teaches the useof continuous connection of tubes and or electrical cable from thesurface to the production formations depths where the tubes are attachedto sand screen systems prior to, during, and after the gravel packoperations such the tubes and screen system do not need to bedisconnected from the surface deployed production tubing. One end of thecontrol tube extends to surface to allow communication and power to becommunicated to the subterranean depth where the sand screen system isdisposed.

This invention apparatus then allows subterranean devices and sensors tobe attached to sand screen systems such that data can be read andsignals and power can be sent to the down hole system.

This invention allows for sand screen systems to reduce or shut offfluid flow, determine the flow characteristics and reservoir propertiesof down hole formations, and to isolate different production zonescompleted simultaneously in a common well bore.

BRIED DESCRIPTION OF THE DRAWING

FIG. 1 depicts a longitudinal sectional view of an adjustable wellscreen assembly according to the invention;

FIG. 2 depicts a schematic side view of an inflow zone of an oil and/orgas production well in which three adjustable well screen assembliesaccording to the present invention are arranged;

FIG. 3 depicts in more detail the upper end of one of the movablesleeves of FIGS. 1 and 2 and the actuator mechanism for axiallytranslating the sleeve within the base pipe; and

FIG. 4 depicts a schematic three dimensional view of an alternativearrangement of a well screen and perforated base pipe and sleeveassembly according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The adjustable screen assembly shown in FIG. 1 comprises an inner sleeve1 having perforations 2 being disposed concentrically inside of a wellscreen's 5 inner diameter base pipe 3 having perforations 4 to allowfluid to flow from the sand screen 5 into the interior 7 of the innersleeve 1. The inner sleeve 1 is axially slidable within the base pipe 3such that appropriate sealing rings 6 can be moved between the secondposition shown in FIG. 1, in which well fluids are permitted to flowthrough the sandscreen 5 and the aligned perforations 4 and 2 of thebase pipe 3 and inner sleeve 1 into the interior of the sleeve 1 and afirst position (not shown) in which the sealing rings 6 close off theperforations 4 in the base pipe 3 such that the fluid flow from thesandscreen 5 into the interior of the sleeve 1 is inhibited or stopped.This axial movement of the inner sleeve 1 relative to the base pipe 3may be initiated by a hydraulic piston and cylinder assembly 8,9 whichis shown in FIG. 3. The hydraulic piston and cylinder assembly 8,9 maybe connected to a hydraulic pump (not shown) at the earth surface by ahydraulic conduit 10.

The adjustable well screen assembly according to the invention maycomprise any suitable combination of electrical power, hydraulic power,or optic powered apparatus that allow communication of power to, andtransmission of data from, the assembly. In the embodiment shown in FIG.3 the inner sleeve 1 is actuated from surface with hydraulic pressuresupplied from surface through the hydraulic conduit 10. In thisembodiment the hydraulic pressure would force the hydraulic piston 8 andassociated perforated inner sleeve 1 to a new position in the perforatedbase pipe 3 changing the rate of flow through the well screen 5.Pressure, temperature, velocity, composition and/or other sensors 11 maybe deployed in or around the sandscreen 5 to indicate the flow, fluid,and pressure changes resulting from the varying sleeve position and saidsensors 11 transmit data to surface via one or more fibre optical and/orelectrical signal transmission conduits 12 attached to the screen 5. Itis also clear to any familiar to the art that said communication andpower to the screen can be achieved by electrical optical,electromagnetic and or acoustic power and signal transmission methods.Hence the invention teaches the use of multiple power and communicationmethods to be used in the invention for both communication with theinventions sensors, and to power the subterranean devices of theinvention.

FIG. 2 illustrates an embodiment of the invention comprising threeadjustable screen assemblies 20A, 20B and 20C each with their own innerinner sleeve 1A, 1B and 1C connected to surface via simultaneouslydisposed power and signal transmission conduits 10 and 12. Hence thisinvention teaches the simultaneous disposal and use of multipleadjustable sand screen assemblies 20A, B and C such that one screen 20Ccan be opened whilst another 20A is substantially closed whilst another20B is partly moved to reduce flow. It is clear to those familiar to theart of well production that said invention can be used to change inflowof several completed production formations without the current industrypractice of well intervention.

In the embodiment shown in FIG. 2 a pair of packers 21 is arrangedaround blank sections of the production tubing 23 between the wire wraps5A, 5B and 5C of three adjustable well screen assemblies 20A, 20B and20C which are each similar to the well screen assembly shown in FIG. 1.These packers 21 form seals in the annular space between the innersurface of the well casing 22 and the production tubing 23 which carriesthe adjustable sand screen assemblies 20A, 20B and 20C. The packers 21are connected to the production tubing 23. The packers 21 are inflatedor set once the production tubing is at the proper depth in the well 25adjacent to perforations 26 that have been shot through the well casing22 and surrounding cement lining 28 into an oil and/or gas bearingformation 27 surrounding the well 25. Once the packers 21 and screenassemblies 20A–C are at the proper depth the packers 21 are set fromsurface using the various methods known to those familiar with the artsuch as hydraulic, electrical, and optical methods. Hence this inventionteaches the simultaneous disposal via the production tubing 23 ofadjustable sandscreen assemblies 20A–C and packers 21 attached thereto.

An additional embodiment of this invention (not shown) teaches thesimultaneous production-tubing disposal of additional tubes andsubterranean devices with the screen system on the production tubing.These devices can include down hole safety valves, down hole chokes,down hole valves and other devices discussed in the literature such thatsaid devices are disposed simultaneously with the well screen systemdeployed on the production tubing.

FIG. 4 shows yet another embodiment of an adjustable well screenassembly according to the invention. In the embodiment shown in FIG. 4 aperforated inner sleeve 40 is rotatably arranged within a perforatedbase pipe 41 such that the perforations are unaligned in one position ofthe sleeve and become aligned when the sleeve is rotated within the basepipe 41. The inner sleeve 40 closely fits within the base pipe 41 andthe contact surfaces may be equipped with a low friction coating toreduce the torque required to rotate the sleeve 40 relative to the basepipe. The patterns of the perforations 42 in the sleeve 40 and base pipe41 may be slightly offset so that when the sleeve 40 is in its secondposition the perforations at the downstream end of the screen assemblyare already slightly offset and that when the sleeve 40 is rotatedtowards its first position the perforations at the downstream end areclosed off earlier than the perforations 42 at the upstream end of theadjustable well screen. The perforations 42 may be circular or haveanother shape to modify the level of fluid influx into the interior ofthe sleeve 40 between the upstream and downstream ends of the sleeve 40as a result of incremental rotation of the sleeve from its first,closed, position towards its second, open, position and vice versa.

While the illustrative embodiments of the invention have been describedwith particularity, it will be understood that various othermodifications will be readily apparent to, and can be easily made by oneskilled in the art without departing from the spirit of the inventionAccordingly, it is not intended that the scope of the following claimsbe limited to the examples and descriptions set forth herein but ratherthat the claims be construed as encompassing all features which would betreated as equivalents thereof by those skilled in the art to which thisinvention pertains.

1. An adjustable well screen assembly comprising; a sand screen which isarranged around a perforated base pipe; and a perforated sleeve which ismovably disposed concentrically relative to the base pipe between afirst and a second position, wherein in said first position of thesleeve, the perforations of the sleeve, and base pipe hydraulicallyisolates from each other and flow of fluids from the outer diameter ofthe screen into the interior of the sleeve is inhibited, and in saidsecond position the perforations of the sleeve and the base pipe areconnected in fluid communication with each other, and fluids arepermitted to flow from the formation through the sand screen and theperforations of the sleeve and base pipe into the interior of the sleeveand wherein the outer diameter of the sleeve is slightly smaller thanthe inner diameter of the base pipe and the sleeve is connected to anactuator, which is designed to rotate and/or axially translate thesleeve within the base pipe; wherein the well screen is equipped withone or more sensors for monitoring physical parameters such as thevelocity and/or composition of the fluids flowing through the screen,and the actuator is designed to move the sleeve between the first andsecond position thereof in response to signals generated by at least oneof the sensors deployed in the screen system.
 2. The well screenassembly of claim 1, wherein the actuator is designed to rotate ortranslate the sleeve such that the sleeve is positionable in a range ofintermediate positions between the first and second position, in whichin the intermediate positions the perforations of the sleeve and basepipe are partially aligned and form adjustable flow restrictions.
 3. Thewell screen assembly of claim 1, wherein the actuator is a hydraulicactuator.
 4. The well screen assembly of claim 1,wherein the sleeve isrotatably arranged within the base pipe.
 5. A hydrocarbon fluidproduction well comprising a hydrocarbon fluid inflow zone which isequipped with a plurality of axially spaced adjustable well screenassemblies of claim 1 wherein the perforated base pipes of adjacentadjustable well screen assemblies are interconnected by blank pipesections on which an expandable packer is arranged which provides afluid seal in the annular space between the outer surface of the blankpipe section and the inner surface of the wellbore.
 6. The hydrocarbonfluid production well of claim 5, wherein the sleeve of each adjustablewell screen assembly is movable between the first and second positionindependently of position of the other sleeve or sleeves.
 7. The wellscreen assembly of claim 1, wherein the actuator is a electrical motor.